Slide rail assembly

ABSTRACT

A slide rail assembly includes a first rail, a second rail, a third rail and a switch member. The second rail is movably mounted between the first rail and the third rail. The switch member is configured to be switched between a first state and a second state. When the switch member is in the second state, the second rail is configured to be driven by the third rail to move to a predetermined position along a retracting direction. When the third rail is moved relative to the second rail at the predetermined position along an extending direction, the switch member is configured to be switched from the second state to the first state.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a slide rail assembly, and moreparticularly, to a slide rail assembly with adjustable extension lengthin order to facilitate maintenance operation of the slide rail assemblyin a limited space.

2. Description of the Prior Art

U.S. Pat. No. 10,244,868 B2 discloses a slide rail assembly comprising afirst rail, a second rail and a third rail. The third rail is arrangedwith a switching member configured to be operated to be at a firstswitch position or a second switch position. When the switching memberis located at the second switch position, the third rail is configuredto drive the second rail to move along a second direction (retractingdirection), such that a total length of the slide rail assembly isreduced to facilitate utilization of the slide rail assembly in a narrowspace. The switching member is arranged on the third rail, and a usercan only operate the switching member manually. If the switching memberis not switched back to the first switch position properly by the user,the rails can not be fully retracted.

For such issue and different market requirements, it is important todevelop various slide rail products.

SUMMARY OF THE INVENTION

The present invention provides a slide rail assembly capable ofswitching a switch member from a state to another state through a sliderail.

According to an embodiment of the present invention, a slide railassembly comprises a first rail, a second rail, a third rail and aswitch member. The second rail is movable relative to the first rail.The third rail is movable relative to the second rail, and the thirdrail is arranged with a driving structure and a front contact feature.The switch member is movable relative to the second rail and configuredto be in one of a first state and a second state. When the second railis located at a first extended position relative to the first rail, theswitch member is operable to switch from the first state to the secondstate. When the third rail is moved from a second extended positionalong a retracting direction, the driving structure of the third rail isconfigured to contact the switch member in the second state to allow thethird rail to drive the second rail to move to a predetermined positionalong the retracting direction. When the third rail is moved apredetermined extended distance relative to the second rail at thepredetermined position along an extending direction, the third rail isconfigured to drive the switch member to switch from the second state tothe first state through the front contact feature.

According to another embodiment of the present invention, a slide railassembly comprises a first rail, a second rail, a third rail and aswitch member. The second rail is movable relative to the first rail.The third rail is movable relative to the second rail, and the thirdrail is arranged with a front contact feature. The switch member ismovable relative to the second rail to be in one of a first state and asecond state. The switch member is operable to switch from the firststate to the second state. The second rail is configured to be locatedat a predetermined position relative to the first rail. When the secondrail is located at a predetermined position relative to the first rail,and when the switch member is switched from the first state to thesecond state, the third rail is configured to drive the switch member toswitch from the second state to the first state through the frontcontact feature during a process of the third rail being moved apredetermined extended distance relative to the second rail at thepredetermined position along an extending direction.

According to another embodiment of the present invention, a slide railassembly comprises a first rail, a second rail, a third rail and aswitch member. The second rail is movable relative to the first rail.The third rail is movably mounted to a passage of the second rail to bemovable relative to the second rail, and the third rail is arranged witha rear contact feature. The switch member is movable relative to thesecond rail to be in one of a first state and a second state. When thethird rail is detached from the passage of the second rail along anextending direction and when the switch member is switched from thefirst state to the second state, the third rail is configured to drivethe switch member to switch from the second state to the first statethrough the rear contact feature during a process of the third railbeing remounted to the passage of the second rail along the retractingdirection.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of the slide rail assembly according to anembodiment of the present invention;

FIG. 2 is an exploded view of a second rail and a switch memberaccording to an embodiment of the present invention;

FIG. 3 is a diagram showing the switch member being in a first stateaccording to an embodiment of the present invention;

FIG. 4 is a diagram showing the switch member being in the first statefrom another viewing angle according to an embodiment of the presentinvention;

FIG. 5 is a diagram showing the switch member being in a second stateaccording to an embodiment of the present invention;

FIG. 6 is a diagram showing the switch member being in the second statefrom another viewing angle according to an embodiment of the presentinvention;

FIG. 7 is a diagram showing internal components of the slide railassembly being in a retracted state according to an embodiment of thepresent invention;

FIG. 8 is a diagram showing the slide rail assembly being moved along anextending direction according to an embodiment of the present invention;

FIG. 9 is a diagram showing the second rail of the slide rail assemblybeing located at a first extended position according to an embodiment ofthe present invention;

FIG. 10 is a diagram showing the slide rail assembly being in anextended state with the switch member being in the first state accordingto an embodiment of the present invention;

FIG. 11 is a diagram showing the slide rail assembly being in theextended state with the switch member being in the second stateaccording to an embodiment of the present invention;

FIG. 12 is a diagram showing the slide rail assembly being moved along aretracting direction according to an embodiment of the presentinvention;

FIG. 13 is a diagram showing a third rail of the slide rail assemblybeing moved along the retracting direction to one position according toan embodiment of the present invention;

FIG. 14 is a diagram showing the second rail being driven by the thirdrail to move relative to a first rail along the retracting directionaccording to an embodiment of the present invention;

FIG. 15 is a diagram showing the second rail being driven by the thirdrail to further move relative to the first rail along the retractingdirection according to an embodiment of the present invention;

FIG. 16 is a diagram showing the second rail being driven by the thirdrail to move along the retracting direction to a predetermined positionrelative to the first rail according to an embodiment of the presentinvention;

FIG. 17 is a diagram showing the second rail being located at thepredetermined position relative to the first rail with the third railbeing moved along the extending direction according to an embodiment ofthe present invention;

FIG. 18 is a diagram showing the third rail being moved along theextending direction to drive the switch member to be in the first stateaccording to an embodiment of the present invention;

FIG. 19 is a diagram showing the switch member being in the first statewhen the third rail is detached from a passage of the second rail alongthe extending direction according to an embodiment of the presentinvention;

FIG. 20 is a diagram showing the switch member being in the second statewhen the third rail is detached from the passage of the second railalong the extending direction according to an embodiment of the presentinvention;

FIG. 21 is a diagram showing the third rail being mounted to the passageof the second rail along the retracting direction according to anembodiment of the present invention;

FIG. 22 is a diagram showing the switch member being switched to thefirst state when the third rail is mounted to the passage of the secondrail along the retracting direction according to an embodiment of thepresent invention;

FIG. 23 is a diagram showing the third rail being moved along theretracting direction to disengage a second engaging member from thefirst rail according to an embodiment of the present invention;

FIG. 24 is a diagram showing the slide rail assembly having a firstlength when the slide rail assembly is configured to carry a carriedobject and located at the first extended position according to anembodiment of the present invention;

FIG. 25 is a diagram showing the slide rail assembly having a secondlength when the second rail of the slide rail assembly is located at thepredetermined position according to an embodiment of the presentinvention; and

FIG. 26 is a diagram showing the second rail of the slide rail assemblybeing located at the predetermined position with the third rail beingdetached from the second rail along the extending direction according toan embodiment of the present invention.

DETAILED DESCRIPTION

As shown in FIG. 1, a slide rail assembly 20 comprises a first rail 22,a second rail 24 and a third rail 26 according to an embodiment of thepresent invention. The second rail 24 is movably mounted between thefirst rail 22 and the third rail 26. Moreover, the first rail 22 has afront end part f1 and a rear end part r1. The first rail 22 comprises anupper wall 28 a, a lower wall 28 b and a longitudinal wall 30 connectedbetween the upper wall 28 a and the lower wall 28 b. A passage isdefined by the upper wall 28 a, the lower wall 28 b and the longitudinalwall 30, and configured to accommodate the second rail 24.

Preferably, the slide rail assembly 20 further comprises a front base 32arranged on the longitudinal wall 30 of the first rail 22, and the frontbase 32 comprises a guiding feature 34 and a blocking feature 36adjacent to the guiding feature 34. In the present embodiment, theguiding feature 34 has an inclined surface or an arc surface.

Preferably, the slide rail assembly 20 further comprises a rear base 38arranged on the longitudinal wall 30 of the first rail 22, and the rearbase 38 comprises a first guiding section 40, a second guiding section42 and an engaging section 44 located between the first guiding section40 and the second guiding section 42. Preferably, each of the firstguiding section 40 and the second guiding section 42 comprises aninclined surface or an arc surface, and the engaging section 44 is anotch, but the present invention is not limited thereto.

Preferably, the first rail 22 is arranged with at least one rearblocking part 46 and at least one front blocking part 48 respectivelyadjacent to the rear end part r1 and the front end part f1. In thepresent embodiment, the first rail 22 is arranged with two rear blockingparts 46 and two front blocking parts 48, but the present invention isnot limited thereto.

The second rail 24 has a front end part f2 and a rear end part r2. Thesecond rail 24 comprises an upper wall 50 a, a lower wall 50 b and alongitudinal wall 52 connected between the upper wall 50 a and the lowerwall 50 b. A passage is defined by the upper wall 50 a, the lower wall50 b and the longitudinal wall 52, and configured to accommodate thethird rail 26. The second rail 24 has a first side L1 and a second sideL2 opposite to the first side L1. The first side L1 of the second rail24 faces the first rail 22, and the second side L2 of the second rail 24faces the third rail 26.

Preferably, the slide rail assembly 20 further comprises a firstengaging mechanism arranged on the longitudinal wall 52 of the secondrail 24. The first engaging mechanism comprises a first engaging member54 and a first elastic member 56 configured to provide an elastic forceto the first engaging member 54. In the present embodiment, the firstengaging member 54 comprises a supporting part 58, an engaging part 60and a mounting feature 62 located between the supporting part 58 and theengaging part 60. The mounting feature 62 of the first engaging member54 is pivotally connected to the second side L2 of the longitudinal wall52 of the second rail 24 through a first pivoting member 64.

Preferably, the longitudinal wall 52 of the second rail 24 has a firstthrough hole 66 communicated with the first side L1 and the second sideL2 of the second rail 24. The engaging part 60 of the first engagingmember 54 passes through the first through hole 66 from the second sideL2 of the second rail 24 to extend to the first side L1 of the secondrail 24. On the other hand, the first elastic member 56 has amain bodypart 68 and an elastic part 70 connected to the main body part 68. Themain body part 68 is connected to the second side L2 of the longitudinalwall 52 of the second rail 24. The elastic part 70 is configured toelastically abut against the first engaging member 54, and the elasticpart 70 is adjacent to the supporting part 58.

Preferably, the slide rail assembly 20 further comprises a secondengaging mechanism arranged on the longitudinal wall 52 of the secondrail 24. The second engaging mechanism comprises a second engagingmember 72 and a second elastic member 74 configured to provide anelastic force to the second engaging member 72. In the presentembodiment, the second engaging member 72 comprises an engaging section78, a supporting section 80 and a connecting feature 82 located betweenthe engaging section 78 and the supporting section 80. The connectingfeature 82 of the second engaging member 72 is pivotally connected tothe second side L2 of the longitudinal wall 52 of the second rail 24through a second pivoting member 84.

Preferably, the longitudinal wall 52 of the second rail 24 has a secondthrough hole 86 communicated with the first side L1 and the second sideL2 of the second rail 24. The engaging section 78 of the second engagingmember 72 passes through the second through hole 86 from the second sideL2 of the second rail 24 to extend to the first side L1 of the secondrail 24. On the other hand, the second elastic member 74 is arranged onthe longitudinal wall 52 of the second rail 24. The second elasticmember 74 is configured to elastically abut against the second engagingmember 72, and the second elastic member 74 is adjacent to the engagingsection 78.

The third rail 26 has a front end part f3 and a rear end part r3. Thethird rail 26 comprises an upper wall 88 a, a lower wall 88 b and alongitudinal wall 90 connected between the upper wall 88 a and the lowerwall 88 b. The longitudinal wall 90 of the third rail 26 is arrangedwith a driving structure 92, a front contact feature 94 and a rearcontact feature 96, and the front contact feature 94 is located betweenthe rear contact feature 96 and the driving structure 92.

Preferably, the longitudinal wall 90 of the third rail 26 is furtherarranged with a working feature 98 and a supporting feature 100.

Preferably, the driving structure 92, the front contact feature 94, therear contact feature 96, the working feature 98 and the supportingfeature 100 are protrusions protruded from the longitudinal wall 90 ofthe third rail 26 to face toward the second side L2 of the second rail24, but the present invention is not limited thereto.

Preferably, a slide assisting device is arranged between each twoadjacent rails of the slide rail assembly 20 to improve smoothness ofrelative longitudinal movement of the two adjacent rails. For example, alower bearing retainer 102 and an upper bearing retainer 104 arearranged inside the passage of the first rail 22 and configured torespectively support the lower wall 50 b and the upper wall 50 a of thesecond rail 24.

Preferably, the lower wall 50 b and the upper wall 50 a of the secondrail 24 are further arranged with a lower pushing part 106 and an upperpushing part 108 respectively configured to abut against rear ends ofthe lower bearing retainer 102 and the upper bearing retainer 104.

As shown in FIG. 2 to FIG. 4, the slide rail assembly 20 furthercomprises a switch member 110 movably arranged on the second rail 24according to an embodiment of the present invention. In the presentembodiment, the switch member 110 is movably arranged on the second rail24 and adjacent to the front end part f2 of the second rail 24, but thepresent invention is not limited thereto. On the other hand, the secondrail 24 has a first limiting part 112, a second limiting part 114 and aspace 116 defined between the first limiting part 112 and the secondlimiting part 114. The space 116 is communicated with the first side L1and the second side L2 of the second rail 24.

Preferably, the switch member 110 is pivotally connected to the firstside L1 of the second rail 24 through a shaft member 118. The switchmember 110 is arranged with a switch part 120 extending to the secondside L2 of the second rail 24.

Preferably, the space 116 is a hole defined by an arc-shaped hole wallof the longitudinal wall 52 of the second rail 24. In addition, thespace 116 has a first accommodating part K1 and a second accommodatingpart K2 communicated with each other. The switch member 110 is arrangedwith a holding feature 111, and the second rail 24 is arranged with amatching feature 25. The holding feature 111 and the matching feature 25are a combination of convex and concave structures matching each other,but the present invention is not limited thereto.

Preferably, the switch member 110 is movable relative to the second rail24 to be in one of a first state S1 (as shown in FIG. 3 and FIG. 4) anda second state S2 (as shown in FIG. 5 and FIG. 6).

Preferably, the switch part 120 of the switch member 110 has a firsthead part 122, a second head part 124 and a body part 126 connectedbetween the first head part 122 and the second head part 124. The firsthead part 122 is located at the first side L1 of the second rail 24, thesecond head part 124 is located at the second side L2 of the second rail24, and the body part 126 is supported by the arc-shaped hole wall atthe first accommodating part K1 and the second accommodating part K2.When the switch member 110 is in the first state S1, the switch part 120of the switch member 110 is located in the first accommodating part K1of the space 116.

Preferably, the switch member 110 is further connected to the secondrail 24 through an auxiliary shaft member 128, and the switch member 110is arranged with a bounded auxiliary guiding hole 130. A contour of theauxiliary guiding hole 130 is substantially in an arc shape. Theauxiliary shaft member 128 passes through a portion of the auxiliaryguiding hole 130. The auxiliary shaft member 128 and the auxiliaryguiding hole 130 are configured to assist the switch member 110 inmoving relative to the second rail 24 within a limited range.

As shown in FIG. 5 and FIG. 6, a user can apply a force F to the switchmember 110 to switch the switch member 110 from the first state S1 tothe second state S2. When the switch member 110 is in the second stateS2, the switch part 120 of the switch member 110 is located in thesecond accommodating part K2 of the space 116, and the holding feature111 and the matching feature 25 abut against each other to hold theswitch member 110 in the second state S2.

As shown in FIG. 7, the slide rail assembly 20 is in a retracted state(the third rail 26 is located at a fully-retracted position R). The rearblocking part 46 of the first rail 22 is configured to block the rearend part r2 of the second rail 24.

Furthermore, the rear base 38 is apart from the front base 32. The firstengaging member 54 is held in a first predetermined state X1 in responseto the elastic force of the first elastic member 56, and the engagingpart 60 of the first engaging member 54 is located at a positioncorresponding to the guiding feature 34 of the front base 32. Thesupporting section 80 of the second engaging member 72 is configured tobe supported by the supporting feature 100 of the third rail 26, inorder to hold the second engaging member 72 in an initial state Y1, suchthat the engaging section 78 of the second engaging member 72 ismisaligned with the rear base 38. In the meantime, the second elasticmember 74 accumulates an elastic force. Moreover, when the switch member110 is in the first state S1, the switch part 120 of the switch member110 is not located at the same horizontal position as the drivingstructure 92, the front contact feature 94 and the rear contact feature96 of the third rail 26.

Preferably, one of the front contact feature 94 of the third rail 26 andthe switch part 120 of the switch member 110 has a guiding surface. Inthe present embodiment, the front contact feature 94 has a guidingsurface 132, and the switch part 120 is a cylinder. The guiding surface132 can be an inclined surface or an arc surface, but the presentinvention is not limited thereto.

Preferably, one of the rear contact feature 96 of the third rail 26 andthe switch part 120 of the switch member 110 has a guiding surface. Inthe present embodiment, the rear contact feature 96 has a guidingsurface 134. The guiding surface 134 can be an inclined surface or anarc surface, but the present invention is not limited thereto.

Preferably, one of the driving structure 92 of the third rail 26 and theswitch part 120 of the switch member 110 has a guiding surface. In thepresent embodiment, the driving structure 92 has a guiding surface 136.The guiding surface 136 can be an inclined surface or an arc surface,but the present invention is not limited thereto. In addition, thedriving structure 92 further has a contact wall 138 (such as a verticalwall).

As shown in FIG. 8, when the second rail 24 is moved relative to thefirst rail 22 along an extending direction D1 to one position, theengaging part 60 of the first engaging member 54 is configured tocontact the guiding feature 34 of the front base 32.

As shown in FIG. 9, when the second rail 24 is further moved relative tothe first rail 22 along the extending direction D1, the engaging part 60of the first engaging member 54 is guided by the guiding feature 34 ofthe front base 32, and the first engaging member 54 is deflectedaccordingly. The first elastic member 56 accumulates an elastic force inresponse to deflection of the first engaging member 54. When the secondrail 24 is moved relative to the first rail 22 to a first extendedposition E1 and the engaging part 60 of the first engaging member 54crosses the guiding feature 34, the elastic part 70 of the first elasticmember 56 releases the elastic force immediately to allow the firstengaging member 54 to return to the first predetermined state X1. In themeantime, the engaging part 60 of the first engaging member 54 isblocked by the blocking feature 36 of the front base 32, in order toprevent the second rail 24 from being moved from the first extendedposition E1 along a retracting direction D2.

As shown in FIG. 10 and FIG. 11, when the second rail 24 is located atthe first extended position E1 relative to the first rail 22, the thirdrail 26 can be further moved relative to the second rail 24 along theextending direction D1 to a second extended position E2. In themeantime, the slide rail assembly 20 is in a fully extended state.

Furthermore, when the second rail 24 is located at the first extendedposition E1 relative to the first rail 22, the switch member 110 can bemanually switched from the first state S1 to the second state S2. Whenthe switch member 110 is in the second state S2, the switch part 120 ofthe switch member 110 is located at the substantially same horizontalposition H as the driving structure 92, the front contact feature 94 andthe rear contact feature 96 of the third rail 26 (as shown in FIG. 11).

Moreover, as shown in FIG. 12 and FIG. 13, when the third rail 26 ismoved relative to the second rail 24 so that the supporting feature 100no longer supports the supporting section 80 of the second engagingmember 72, the second engaging member 72 is switched from the initialstate Y1 to an non-initial state Y2 in response to the elastic force ofthe second elastic member 74. In addition, the first engaging member 54further comprises a disengaging part 140 adjacent to the engaging part60. Preferably, one of the disengaging part 140 and the working feature98 has an inclined surface or an arc surface. In the present embodiment,the disengaging part 140 has an inclined surface (or an arc surface),but the present invention is not limited thereto.

As shown in FIG. 11 to FIG. 13, the switch member 110 is in the secondstate S2. When the third rail 26 is moved a distance from the secondextended position E2 relative to the second rail 24 at the firstextended position E1 along the retracting direction D2, the workingfeature 98 of the third rail 26 contacts the disengaging part 140 of thefirst engaging member 54 to generate a working force, such that thefirst engaging member 54 is rotated from the first predetermined stateX1 (as shown in FIG. 12) to a second predetermined state X2 (as shown inFIG. 13) in response to the working force. As such, the engaging part 60of the first engaging ember 54 is no longer blocked by the blockingfeature 36 of the front base 32, so as to allow the second rail 24 to bemoved from the first extended position E1 along the retracting directionD2. When the third rail 26 is moved from the second extended position E2along the retracting direction D2, the contact wall 138 of the drivingstructure 92 contacts the switch part 120 of the switch member 110 inthe second state S2, such that the third rail 26 is configured to drivethe second rail 24 to move along the retracting direction D2.

As shown in FIG. 14 to FIG. 16, the second engaging member 72 furthercomprises a disengaging section 142 adjacent to the supporting section80. Preferably, one of the disengaging section 142 and the supportingfeature 100 has an inclined surface or an arc surface. In the presentembodiment, the disengaging section 142 has an inclined surface (or anarc surface), but the present invention is not limited thereto.

When the third rail 26 is moved along the retracting direction D2, thecontact wall 138 of the driving structure 92 contacts the switch part120 of the switch member 110 in the second state S2, such that the thirdrail 26 can drive the second rail 24 to move along the retractingdirection D2 to a predetermined position P (as shown in FIG. 16). Whenthe second rail 24 is located at the predetermined position P, thesecond rail 24 is engaged with the rear base 38 through the secondengaging mechanism.

Specifically, during a process of the second rail 24 being moved to thepredetermined position P along the retracting direction D2, the engagingsection 78 of the second engaging member 72 in the non-initial state Y2contacts the second guiding section 42 of the rear base 38 (as shown inFIG. 14) to generate a working force, such that the second engagingmember 72 is rotated to be no longer in the non-initial state Y2, andthe second elastic member 74 accumulates an elastic force (as shown inFIG. 15). When the second rail 24 is located at the predeterminedposition P, the second engaging member 72 returns to the non-initialstate Y2 in response to the elastic force of the second elastic member74, such that the engaging section 78 of the second engaging member 72is engaged with the engaging section 44 of the rear base 38 (as shown inFIG. 16) in order to prevent the second rail 24 from being movedrelative to the first rail 22 from the predetermined position P alongthe extending direction D1 or the retracting direction D2.

Moreover, when the second rail 24 is located at the predeterminedposition P relative to the first rail 22, the engaging section 78 of thesecond engaging member 72 is engaged with the engaging section 44 of therear base 38. In the meantime, a total length of the slide rail assembly20 is reduced and the second rail 24 is in a locked state. Therefore,the slide rail assembly 20 requires a smaller space to pull out thethird rail 26 of the slide rail assembly 20 relative to the second rail24 along the extending direction D1, so as to facilitate use in alimited space. On the other hand, when the second rail 24 is located atthe predetermined position P and the driving structure 92 of the thirdrail 26 contacts the switch member 110 in the second state S2, the thirdrail 26 is prevented from being moved relative to the second rail 24along the retracting direction D2.

As shown in FIG. 17 to FIG. 19, when the second rail 24 is located atthe position P relative to the first rail 22, the third rail 26 can bemoved relative to the second rail 24 along the extending direction D1.When the third rail 26 is moved a predetermined extended distance alongthe extending direction D1, the guiding surface 132 of the front contactfeature 94 contacts the switch part 120 of the switch member 110, suchthat the third rail 26 is configured to drive the switch member 110 toswitch from the second state S2 (as shown in FIG. 17) to the first stateS1 (as shown in FIG. 18), and the third rail 26 can be further detachedfrom the second rail 24 located at the predetermined position P alongthe extending direction D1 (as shown in FIG. 19).

Therefore, when the third rail 26 is moved relative to the second rail24 at the predetermined position P along the extending direction D1, thethird rail 26 can drive the switch member 110 to switch from the secondstate S2 to the first state S1 through the front contact feature 94, soas to ensure that the switch member 110 is in the first state S1.Especially, when the third rail 26 is detached from the second rail 24along the extending direction D1, it can be ensure that the switchmember 110 is in the first state S1.

As shown in FIG. 19 and FIG. 20, after the third rail 26 is detachedfrom the passage of the second rail 24 along the extending direction D1,the switch member 110 is in the first state S1 (as shown in FIG. 19).However, if the switch member 110 is accidentally switched from thefirst state S1 to the second state S2 (as shown in FIG. 20) due to otherfactors (such as an external force), the third rail 26 can drive theswitch member 110 to switch from the second state S2 to the first stateS1 through the rear contact feature 96 during a process of the thirdrail 26 being remounted to the passage of the second rail 24 along theretracting direction D2.

As shown in FIG. 20 to FIG. 22, during the process of the third rail 26being remounted to the passage of the second rail 24, the third rail 26is configured to drive the switch member 110 to switch from the secondstate S2 (as shown in FIG. 21) to the first state S1 (as shown in FIG.22) through the guiding surface 134 of the rear contact feature 96contacting the switch part 120 of the switch member 110.

As shown in FIG. 16 and FIG. 23, when the third rail 26 is movedrelative to the second rail 24 at the predetermined position P along theretracting direction D2, the supporting feature 100 of the third rail 26contacts the disengaging section 142 of the second engaging member 72 togenerate a working force, such that the second engaging member 72 isswitched from the non-initial state Y2 (as shown in FIG. 16) to theinitial state Y1 (as shown in FIG. 23), and the supporting feature 100of the third rail 26 is configured to support the supporting section 80of the second engaging member 72 once again to hold the second engagingmember 72 in the initial state Y1. Thereby, the engaging section 78 ofthe second engaging member 72 is no longer engaged with the engagingsection 44 of the rear base 38, so as to allow the second rail 24 toretract relative to the first rail 22 from the predetermined position Palong the retracting direction D2. Since the switch member 110 isswitched to the first state S1, the third rail 26 can be moved relativeto the second rail 24 along the retracting direction D2 to thefully-retracted position R (please refer to FIG. 7).

Therefore, when the switch member 110 is in the first state S1 (as shownin FIG. 22) , the third rail 26 can be moved relative to the second rail24 along the retracting direction D2 to the fully-retracted position R(please refer to FIG. 7).

As shown in FIG. 24 to FIG. 26, according to aforementioned arrangement,the slide rail assembly 20 of the present invention is applicable in anarrow space. The first rail 22 is configured to be mounted to a rack(not shown in figures). The third rail 26 is configured to a carry acarried object 144. When the second rail 24 is located at the firstextended position E1 relative to the first rail 22, the slide railassembly 20 has a first length M1. The third rail 26 can be movedrelative to the second rail 24 along the extending direction D1 to thesecond extended position E2 (as shown in FIG. 24), and a first space W1is formed between the front end part f3 of the third rail 26 (or thecarried object 144) and an obstruction 146 (such as a wall, a door orother surrounding obstruction). However, if the first space W1 is toonarrow, an on-site user cannot smoothly perform related maintenanceoperations on the carried object 144 or the slide rail assembly 20.Therefore, the user can move the second rail 24 relative to the firstrail 22 from the first extended position E1 to the predeterminedposition P along the retracting direction D2 (please refer to FIG. 25and FIG. 16), such that a second space W2 wider than the first space W1is formed between the front end part f3 of the third rail 26 and theobstruction 146, in order to allow the on-site user to smoothly performdetachment of the carried object 144 or related maintenance operationsof the slide rail assembly 20. When the second rail 24 is located at thepredetermined position P relative to the first rail 22, the slide railassembly 20 is shortened to a second length M2, and the second length M2is smaller than the first length M1. When the second rail 24 is locatedat the predetermined position P relative to the first rail 22, the thirdrail 26 can be detached from the second rail 24 along the extendingdirection D1.

Therefore, the slide rail assembly 20 according to embodiments of thepresent invention is characterized in that: the switch member 110 can beswitched with a fool-proof function by pulling out or re-inserting aslide rail. That is, the user can switch the switch member 110 from thesecond state S2 to the first state S1 without manually moving the switchmember 110. According to such arrangement, while the slide rail assembly20 is applied in the narrow space, it is ensured that the third rail 26can be moved relative to the second rail 24 along the retractingdirection D2 to the fully-retracted position R.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

What is claimed is:
 1. A slide rail assembly, comprising: a first rail;a second rail movable relative to the first rail; a third rail movablerelative to the second rail, the third rail being arranged with adriving structure and a front contact feature; and a switch membermovable relative to the second rail and configured to be in one of afirst state and a second state, wherein the switch member is arrangedwith a switch part; wherein when the second rail is located at a firstextended position relative to the first rail, the switch member isoperable to switch from the first state to the second state; whereinwhen the third rail is moved from a second extended position along aretracting direction and when the switch member is in the second state,the switch part of the switch member is configured to block a movingpath of the driving structure, and the driving structure of the thirdrail is configured to continuously push the switch member in the secondstate along the retracting direction to drive the second rail to move toa predetermined position along the retracting direction; wherein whenthe third rail is moved a predetermined extended distance relative tothe second rail at the predetermined position along an extendingdirection, the third rail is configured to drive the switch member toswitch from the second state to the first state through the frontcontact feature.
 2. The slide rail assembly of claim 1, wherein thethird rail is further arranged with a rear contact feature; when thethird rail is detached from a passage of the second rail along theextending direction and when the switch member is switched from thefirst state to the second state, the third rail is configured to drivethe switch member to switch from the second state to the first statethrough the rear contact feature during a process of the third railbeing remounted to the passage of the second rail along the retractingdirection.
 3. The slide rail assembly of claim 2, wherein the secondrail is movably mounted between the first rail and the third rail, andthe second rail has a first side and a second side; and wherein thefirst side of the second rail faces the first rail, and the second sideof the second rail faces the third rail.
 4. The slide rail assembly ofclaim 3, wherein the second rail has a first limiting part, a secondlimiting part and a space defined between the first limiting part andthe second limiting part, and the space is communicated with the firstside and the second side of the second rail; the switch member ispivotally connected to the first side of the second rail through a shaftmember, and the switch part is configured to pass through a portion ofthe space from the first side of the second rail to extend to the secondside of the second rail.
 5. The slide rail assembly of claim 4, whereinwhen the switch member is in the second state, the switch part of theswitch member, the driving structure, the front contact feature and therear contact feature are located at a substantially same horizontalposition.
 6. The slide rail assembly of claim 4, wherein one of thefront contact feature of the third rail and the switch part of theswitch member has a guiding surface.
 7. The slide rail assembly of claim4, wherein one of the rear contact feature of the third rail and theswitch part of the switch member has a guiding surface.
 8. The sliderail assembly of claim 1, wherein when the second rail is located at thepredetermined position and when the driving structure of the third railcontacts the switch member in the second state, the third rail isprevented from being moved relative to the second rail along theretracting direction.
 9. The slide rail assembly of claim 8, whereinwhen the switch member is in the first state, the driving structure ofthe third rail is spaced from the switch member, so as to allow thethird rail to be moved relative to the second rail along the retractingdirection to a fully-retracted position.
 10. The slide rail assembly ofclaim 1, wherein when the second rail is located at the first extendedposition relative to the first rail, the slide rail assembly has a firstlength; and wherein when the second rail is located at the predeterminedposition relative to the first rail, the slide rail assembly has asecond length smaller than the first length.
 11. The slide rail assemblyof claim 1, further comprising a front base arranged on the first rail,and a first engaging mechanism arranged on the second rail; wherein thefront base comprises a blocking feature; wherein when the second rail islocated at the first extended position, the first engaging mechanism islocated adjacent to the blocking feature of the front base, in order toprevent the second rail from being moved from the first extendedposition along the retracting direction; wherein the first engagingmechanism comprises a first engaging member and a first elastic memberconfigured to provide an elastic force to the first engaging member;wherein when the second rail is located at the first extended position,the first engaging member is located adjacent to the blocking feature ofthe front base in response to the elastic force of the elastic member.12. The slide rail assembly of claim 11, further comprising a rear basearranged on the first rail, and a second engaging mechanism arranged onthe second rail; wherein when the second rail is moved from the firstextended position to the predetermined position along the retractingdirection, the second rail is engaged with the rear base through thesecond engaging mechanism, in order to prevent the second rail frombeing moved from the predetermined position along the extendingdirection; wherein the second engaging mechanism comprises a secondengaging member and a second elastic member configured to provide anelastic force to the second engaging member; wherein when the secondrail is located at the predetermined position, the second engagingmember is configured to be engaged with the rear base in response to theelastic force of the second elastic member.
 13. A slide rail assembly,comprising: a first rail; a second rail movable relative to the firstrail; a third rail movable relative to the second rail, the third railbeing arranged with a driving structure and a front contact feature; anda switch member movable relative to the second rail to be in one of afirst state and a second state, wherein the switch member is arrangedwith a switch part; wherein the switch member is operable to switch fromthe first state to the second state; wherein the second rail isconfigured to be located at a predetermined position relative to thefirst rail; wherein when the second rail is located at a predeterminedposition relative to the first rail, and when the switch member isswitched from the first state to the second state, the third rail isconfigured to drive the switch member to switch from the second state tothe first state through the front contact feature during a process ofthe third rail being moved a predetermined extended distance relative tothe second rail at the predetermined position along an extendingdirection; wherein when the second rail is located at a first extendedposition relative to the first rail, the switch member is operable toswitch from the first state to the second state; wherein when the thirdrail is moved from a second extended position along a retractingdirection and when the switch member is in the second state, the switchpart of the switch member is configured to block a moving path of thedriving structure, and the driving structure of the third rail isconfigured to continuously push the switch member in the second statealong the retracting direction to drive the second rail to move to thepredetermined position along the retracting direction.
 14. The sliderail assembly of claim 13, wherein the second rail is movably mountedbetween the first rail and the third rail, and the second rail has afirst side and a second side; wherein the first side of the second railfaces the first rail, and the second side of the second rail faces thethird rail; wherein the second rail has a first limiting part, a secondlimiting part and a space defined between the first limiting part andthe second limiting part, and the space is communicated with the firstside and the second side of the second rail; wherein the switch memberis pivotally connected to the first side of the second rail through ashaft member, and the switch part is configured to pass through aportion of the space from the first side of the second rail to extend tothe second side of the second rail.
 15. The slide rail assembly of claim13, further comprising a front base arranged on the first rail, and afirst engaging mechanism arranged on the second rail; wherein the frontbase comprises a blocking feature; wherein when the second rail islocated at the first extended position, the first engaging mechanism islocated adjacent to the blocking feature of the front base, in order toprevent the second rail from being moved from the first extendedposition along the retracting direction; wherein the slide rail assemblyfurther comprises a rear base arranged on the first rail, and a secondengaging mechanism arranged on the second rail; wherein when the secondrail is moved from the first extended position to the predeterminedposition along the retracting direction, the second rail is configuredto be engaged with the rear base through the second engaging mechanism,in order to prevent the second rail from being moved from thepredetermined position along the extending direction.
 16. A slide railassembly, comprising: a first rail; a second rail movable relative tothe first rail; a third rail movably mounted to a passage of the secondrail to be movable relative to the second rail, the third rail beingarranged with a driving structure and a rear contact feature; and aswitch member movable relative to the second rail to be in one of afirst state and a second state, wherein the switch member is arrangedwith a switch part; wherein when the third rail is detached from thepassage of the second rail along an extending direction and when theswitch member is switched from the first state to the second state, thethird rail is configured to drive the switch member to switch from thesecond state to the first state through the rear contact feature duringa process of the third rail being remounted to the passage of the secondrail along a retracting direction; wherein when the second rail islocated at a first extended position relative to the first rail, theswitch member is operable to switch from the first state to the secondstate; wherein when the third rail is moved from a second extendedposition along the retracting direction and when the switch member is inthe second state, the switch part of the switch member is configured toblock a moving path of the driving structure, and the driving structureof the third rail is configured to continuously push the switch memberin the second state along the retracting direction to drive the secondrail to move to the predetermined position along the retractingdirection.
 17. The slide rail assembly of claim 16, wherein the secondrail is movably mounted between the first rail and the third rail, andthe second rail has a first side and a second side; wherein the firstside of the second rail faces the first rail, and the second side of thesecond rail faces the third rail; wherein the second rail has a firstlimiting part, a second limiting part and a space defined between thefirst limiting part and the second limiting part, and the space iscommunicated with the first side and the second side of the second rail;wherein the switch member is pivotally connected to the first side ofthe second rail through a shaft member, and the switch member isarranged with a switch part passing through a portion of the space fromthe first side of the second rail to extend to the second side of thesecond rail.
 18. The slide rail assembly of claim 17, further comprisinga front base arranged on the first rail, and a first engaging mechanismarranged on the second rail; wherein the front base comprises a blockingfeature; wherein when the second rail is located at the first extendedposition, the first engaging mechanism is located adjacent to theblocking feature of the front base, in order to prevent the second railfrom being moved from the first extended position along the retractingdirection.
 19. The slide rail assembly of claim 18, further comprising arear base arranged on the first rail, and a second engaging mechanismarranged on the second rail; wherein when the second rail is moved fromthe first extended position to the predetermined position along theretracting direction, the second rail is configured to be engaged withthe rear base through the second engaging mechanism, in order to preventthe second rail from being moved from the predetermined position alongthe extending direction.